Bacteriological and histological studies of the small intestine of rats treated with mecamylamine

Abstract

and the Ipswich and East Suffolk Hospital EDITORIAL SYNOPSIS Rats were injected intraperitoneally with mecamylamine (Inversine) in doses that were believed to have reduced peristaltic activity in the small intestine. Large numbers of Escherichia coli were present throughout the lumen of the small intestine of animals treated for two or three days and killed within three hours of the last dose of the drug. Histological changes in the small intestinal mucosa of these animals included an increase in the number of goblet cells and shortening and thickening of the villi. Bacteria invaded the intestinal wall of some of the animals. Animals killed 24 hours after the last dose of the drug showed no significant change from the normal controls.The findings support the hypothesis that bacteria are removed mechanically from the normal small intestine by peristalsis. Certain of the histological changes are similar to those seen in the small intestine in malabsorptive conditions in man and the relationship between hypomotility, the bacterial population, and malabsorption is discussed.

Steatorrhoea in rats with an intestinal cul-de-sac

“…The possible importance of bacterial invasion of the intestinal wall has recently been discussed by Dixon and Paulley (1963). Since we did not observe invasion of the villi by microorganisms (Fig.…”

The Pathogenesis of Gastrointestinal Bacterial Overgrowth

“…Pharmacological suppression of intestinal peristalsis in experimental animals leads to bacterial colonization of small bowel by all types of bacteria present in the gut, including Gram-negative bacilli [100,184,185]. Similar studies cannot be performed in man, but patients taking opioids regularly show changes of intestinal motor activity with a slowing of peristalsis and transit resulting in constipation.…”

“…Later studies, of which those by Dack and Petran [96], Dixon [99] and Dixon and Paulley [100] are of particular importance, provided considerable further evidence that intestinal peristalsis is the main line of defense against bacterial colonization of the small bowel. This was also concluded by Donaldson [101][102][103] when he reviewed host defense mechanisms in 1964.…”

Influence of gastric pH on gastric and jejunal flora.

“…In addition to the interval after the last meal and the pH of the gastric juice, they include the motility of the tract and various pathological conditions. Dixon and Paulley (1963) postulated that there was a direct relationship between the bacterial population of the small intestine and the hypomotility of malabsorption. Using rats which they injected intraperitoneally with mecamylamine to reduce the peristalsis of the small intestine, they found very large numbers of E. coli present in the lumen of the intestine.…”